1. Field of the Invention
The present invention relates to a method of manufacturing a silicon carbide (SiC) single crystal.
2. Description of the Related Art
Conventionally, an SiC is expected to be used for a device having a high breakdown voltage. In the SiC, a crystal defect such as a dislocation and a stacking fault may generate during a crystal growth. In order to reduce the crystal defect, various methods are disclosed.
For example, in a method disclosed in U.S. 2007/0221119 A (corresponding to JP-A-2005-324994), an SiC single crystal is epitaxially grown on a surface of 4H-SiC that inclines from a (0001) plane toward a <11-20> axial direction at an off-angle greater than or equal to 12 degrees and less than 30 degrees so that a crystal defect and an impurity concentration of the SiC single crystal is reduced.
However, even when the SiC single crystal is epitaxially grown on the surface of 4H-SiC that inclines from the (0001) plane toward the <11-20> axial direction at the off-angle greater than or equal to 12 degrees and less than 30 degrees, it is difficult to restrict an inheritance of a dislocation.
In a method disclosed in U.S. Pat. No. 6,890,600 (corresponding to JP-A-2003-119097), an SiC single crystal is grown on a (1-100) plane and a (11-20) plane in order, and finally, the SiC single crystal is grown on a (0001) plane so that a crystal defect of the SiC single crystal is reduced.
Even when the SiC single crystal is grown using various planes, a stacking fault that generates during an A-plane growth may change into a threading dislocation during a C-plane growth and a defect may be inherited. The threading dislocation includes a threading spiral growth and a threading edge dislocation.
JP-A-2005-350278 discloses a method in which grooves are provided on a surface of an SIC single crystal and the SIC single crystal is grown on side surfaces of the grooves in a horizontal direction so that a crystal defect is restricted from growing in a <0001> direction and the crystal defect is reduced.
Even when the SIC single crystal is grown on the side surfaces of the grooves in the horizontal direction, a direction of a dislocation is not always parallel to a growth direction. Therefore, it is difficult to restrict a dislocation in the <0001> direction completely.
Thus, the above-described methods are difficult to restrict an inheritance of a crystal defect in a growth direction of the SiC single crystal during a crystal growth and are difficult to restrict the crystal defect sufficiently.